[PATCH] ARM: dts: rockchip: remove cap-mmc-highspeed property from mk808 &mmc0 node

[PATCH] ARM: dts: rockchip: remove cap-mmc-highspeed property from mk808 &mmc0 node

[Johan Jonker]

On the MK808 only a microSD slot is connected with the SDMMC Host Controller,
so remove the cap-mmc-highspeed property from the &mmc0 node.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
---
 arch/arm/boot/dts/rk3066a-mk808.dts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/boot/dts/rk3066a-mk808.dts b/arch/arm/boot/dts/rk3066a-mk808.dts
index 9790bc63b..b67f5cb51 100644
--- a/arch/arm/boot/dts/rk3066a-mk808.dts
+++ b/arch/arm/boot/dts/rk3066a-mk808.dts
@@ -123,7 +123,6 @@
 
 &mmc0 {
 	bus-width = <4>;
-	cap-mmc-highspeed;
 	cap-sd-highspeed;
 	vmmc-supply = <&vcc_sd>;
 	status = "okay";
-- 
2.20.1

Re: [PATCH] ARM: dts: rockchip: remove cap-mmc-highspeed property from mk808 &mmc0 node

[Robin Murphy]

On 2021-08-20 14:19, Johan Jonker wrote:
> On the MK808 only a microSD slot is connected with the SDMMC Host Controller,
> so remove the cap-mmc-highspeed property from the &mmc0 node.

Why, does it do any harm? It's perfectly possible to connect a 
full-sized card to a microSD slot with an adapter. I came across my old 
SDIO WiFi card a while back and tried it that way for a giggle, but 
unfortunately it turned out not to be a chipset supported by any 
upstream driver.

Robin.

> Signed-off-by: Johan Jonker <jbx6244@gmail.com>
> ---
>   arch/arm/boot/dts/rk3066a-mk808.dts | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/rk3066a-mk808.dts b/arch/arm/boot/dts/rk3066a-mk808.dts
> index 9790bc63b..b67f5cb51 100644
> --- a/arch/arm/boot/dts/rk3066a-mk808.dts
> +++ b/arch/arm/boot/dts/rk3066a-mk808.dts
> @@ -123,7 +123,6 @@
>   
>   &mmc0 {
>   	bus-width = <4>;
> -	cap-mmc-highspeed;
>   	cap-sd-highspeed;
>   	vmmc-supply = <&vcc_sd>;
>   	status = "okay";
> 

Re: [PATCH] ARM: dts: rockchip: remove cap-mmc-highspeed property from mk808 &mmc0 node

[Johan Jonker]

On 8/20/21 4:17 PM, Robin Murphy wrote:
> On 2021-08-20 14:19, Johan Jonker wrote:
>> On the MK808 only a microSD slot is connected with the SDMMC Host
>> Controller,
>> so remove the cap-mmc-highspeed property from the &mmc0 node.
> 
> Why, does it do any harm? 

Harm not. Example rk3066 u-boot:

>>>>sd_select_mode_and_width
sd card: widths [4, 1, \b\b] modes [MMC legacy, SD High Speed (50MHz), UHS
SDR12 (25MHz), UHS SDR25 (50MHz), \b\b]
host: widths [4, 1, \b\b] modes [MMC legacy, MMC High Speed (26MHz), SD
High Speed (50MHz), MMC High Speed (52MHz), \b\b]
trying mode SD High Speed (50MHz) width 4 (at 50 MHz)

I would say only advertise host capabilities that are under normal
circumstances occur. How realistic is it to use a TF/Micro SD TO SD Card
Extension Cable Adapter (giggle) for a deprecated mmc card?

Johan

It's perfectly possible to connect a
> full-sized card to a microSD slot with an adapter. I came across my old
> SDIO WiFi card a while back and tried it that way for a giggle, but
> unfortunately it turned out not to be a chipset supported by any
> upstream driver.
> 
> Robin.
> 
>> Signed-off-by: Johan Jonker <jbx6244@gmail.com>
>> ---
>>   arch/arm/boot/dts/rk3066a-mk808.dts | 1 -
>>   1 file changed, 1 deletion(-)
>>
>> diff --git a/arch/arm/boot/dts/rk3066a-mk808.dts
>> b/arch/arm/boot/dts/rk3066a-mk808.dts
>> index 9790bc63b..b67f5cb51 100644
>> --- a/arch/arm/boot/dts/rk3066a-mk808.dts
>> +++ b/arch/arm/boot/dts/rk3066a-mk808.dts
>> @@ -123,7 +123,6 @@
>>     &mmc0 {
>>       bus-width = <4>;
>> -    cap-mmc-highspeed;
>>       cap-sd-highspeed;
>>       vmmc-supply = <&vcc_sd>;
>>       status = "okay";
>>

Re: [PATCH] ARM: dts: rockchip: remove cap-mmc-highspeed property from mk808 &mmc0 node

[Robin Murphy]

On 2021-08-20 15:41, Johan Jonker wrote:
> 
> 
> On 8/20/21 4:17 PM, Robin Murphy wrote:
>> On 2021-08-20 14:19, Johan Jonker wrote:
>>> On the MK808 only a microSD slot is connected with the SDMMC Host
>>> Controller,
>>> so remove the cap-mmc-highspeed property from the &mmc0 node.
>>
>> Why, does it do any harm?
> 
> Harm not. Example rk3066 u-boot:
> 
>>>>> sd_select_mode_and_width
> sd card: widths [4, 1, \b\b] modes [MMC legacy, SD High Speed (50MHz), UHS
> SDR12 (25MHz), UHS SDR25 (50MHz), \b\b]
> host: widths [4, 1, \b\b] modes [MMC legacy, MMC High Speed (26MHz), SD
> High Speed (50MHz), MMC High Speed (52MHz), \b\b]
> trying mode SD High Speed (50MHz) width 4 (at 50 MHz)
> 
> I would say only advertise host capabilities that are under normal
> circumstances occur. How realistic is it to use a TF/Micro SD TO SD Card
> Extension Cable Adapter (giggle) for a deprecated mmc card?

Well, if you want a far more realistic example:

https://www.hardkernel.com/shop/emmc-module-reader-board-for-os-upgrade/

Who are we to dictate what "normal circumstances" are, and what do we 
gain by removing support for modes that could work fine and at least be 
useful to someone on occasion?

Robin.